*{  
    padding:0;
    margin:0;
    list-style: none;
    text-decoration: none;
    box-sizing: border-box;
    /* height: 100%; */
}
html,body,.app{
    height:100%;
    font-size: 14px;
}
.header {
  width: 100%;
  padding: 0 16px;
  height: 50px;
  line-height: 50px;
  background-color: #1890ff;
  color: #fff;
}